1. Field of the Invention
This invention relates to vibrating motors, and more particularly to a novel construction of a main frame and center clamp for vibrating motors.
2. Description of the Prior Art
The vibrating motors to which this invention relates are characterized by a main frame and a center clamp with a stack of vibrator bars interposed between the main frame and the center clamp. The opposite ends of the vibrator bars are fixedly secured to the main frame, and the center clamp is fixedly secured to the vibrator bars at a position intermediate the opposite ends thereof. The stack of vibrator bars secured in this manner to the main frame and to the center clamp constitute the flexible element in the vibrating motor, which permits the relative vibratory movement of the main frame and the center clamp.
In the main frame there is a stator, which is an electromagnet, that is alternately energized and de-energized, to periodically magnetically excite the stator. In the center clamp there is an armature that is disposed opposite the stator, with a small air gap between the stator and the armature. When the stator is energized, during one-half period of magnetic excitation, the armature and the center clamp are drawn towards the stator, flexing the vibrator bars in the direction of the stator. When the stator is de-energized, during the other half period when the stator is not magnetically excited, the armature and the center clamp are released from the magnetic force, whereby the vibrator bars spring back and flex in the opposite direction. Such alternate flexing action of the spring bars produces the vibration of the main frame and the center clamp relatively to each other.
In a typical construction of the vibrating motor, the main frame is made as the heavy element, which is relateively heavier than the center clamp and the part to which the center clamp is attached. A typical use of a vibrating motor is for a vibrating feeder, in which there is a feeding trough attached to the center clamp, and this feeding trough with the material that is in the trough then becomes part of the vibrated mass.
It has been customary to form the main frame and the center clamp as relatively heavy castings to provide the desired strength and rigidity, and also to form the main frame as the relatively heavier element of the assembly, whereby the vibration will manifest itself in the vibration of the center clamp and the working element which is secured to the center clamp. In the case of the vibrating feeder, the feeder trough is secured to the center clamp and is the working element. Such a construction is illustrated in the patent to Weyandt, U.S. Pat. No. 2,356,961, issued Aug. 29, 1944, for Vibratory Electric Motor. In this patent the main frame is formed as a massive casting, and the center clamp similarly is formed as a casting in the typical manner of the construction of such vibrating motors.